Filling In Pompeii Gaps by Computer

By MALCOLM W. BROWNE

Published: July 13, 1990

During the 242 years since their discovery, the ruins of Pompeii have been excavated, studied, looted, sold, admired and exhibited, and one might wonder whether the ancient Roman port could still harbor any surprises. But an exhibition that opened this week at the I.B.M. Gallery of Science and Art demonstrates that the appeal of Pompeii is as fresh and compelling as ever.

The theme of the show, which Fiat Engineering and I.B.M. Italy took two years to organize, is that new computer technology can tease new archeological insights from old rubble. Computer techniques developed to reconstruct some of the images of ancient Pompeii, presented at the exhibition, give archeologists some powerful new tools, I.B.M.'s officials claim.

But even lacking any interest in computers, a visitor to ''Rediscovering Pompeii'' can expect a treat. Some 200 artifacts, many never displayed before, include sumptuous mural paintings, a striking assortment of marble and bronze figures and portrait busts, and a fascinating collection of tools, kitchen utensils and household implements.

The entrance to the exhibition provides some nasty reminders of how Pompeii met its apocalyptic end on Aug. 24, A.D. 79, when Mount Vesuvius spewed searing-hot gases and pumice over a large region, swiftly burying the town and nearby Herculaneum. Some 2,000 of Pompeii's 8,000 to 12,000 inhabitants died on the spot, including a young woman who is now on display at the I.B.M. exhibition, still encased in her volcanic-rock cocoon.

A Look at Daily Life

Vesuvius brought immortality as well as horror to Pompeii and Herculaneum by preserving the two towns as geological snapshots, in which every detail was faithfully recorded. Because of the tragedy, archeologists know much more about daily life in first-century Rome than they know about many more recent civilizations.

Some of the Roman devices in the exhibition seem startlingly modern. A bronze hydraulic valve that was part of Pompeii's elaborate plumbing system looks (apart from its green patina) as if it had come from a 20th-century hardware store. Presses, drills, sieves, a food warmer and other gadgets underscore the truism that Roman technology reached amazing heights. This technology included a mighty aqueduct from the reign of the Emperor Augustus, which spawned a welter of beautifully decorated and ingenious fountains throughout the town.

The displays include a generous sample of gold jewelry (some set with gleaming emeralds) and some mosaic panels and erotic pottery.

Computer technology was applied especially fruitfully in resurrecting texts from charred papyrus documents, said Dr. Stefano Bruschini, the exhibition's technical adviser from I.B.M. Italy. By using computer enhancement techniques, scientists can now heighten the contrast between the remains of inked letters and the burned papyrus on which they were written, thereby making the texts legible.

Computers and Restoration

Computers were also used in restoring some of the large frescoes on display. Restorers did not try to replace missing pieces with new images, but instead filled them in with a background pattern of colors that from a distance looks like part of the painting. ''Of course, we don't want restored portions confused with the original,'' Dr. Bruschini said, ''so we make sure that a viewer close to a fresco can spot the restoration for what it is. The computer mixes colors for us to try them out electronically before we use real pigments for the restoration.''

In any case, the glowing colors that remain in the original painting are not what they were before Vesuvius erupted; archeologists explain that the heat of the pumice markedly changed the colors of pigments in contact with the volcanic ash. In general, the original colors were lighter than they now look.

''That is particularly true of the color we call Pompeiian red,'' Dr. Bruschini said. ''The Pompeiian artist's red pigment was based on an iron compound that became much darker when it was buried in hot pumice.''

I.B.M.'s computer experts created a huge data base for Pompeii, including the positions and shapes of buildings, baths and other features that permit a mathematical reconstruction of the town. Among the fruits of this work is a large computer-generated map of Pompeii that is interesting in itself and that will help in future excavations of the town. Dr. Baldassare Conticello, the Italian Government's Superintendent for Archeology in Pompeii, said at a news conference this week that more than 50 acres of Pompeii remained to be excavated; the only excavation of the site currently in progress is intended primarily to train the archeologists working at it.

'Interactive' Terminals

''Rediscovering Pompeii'' is sprinkled with ''interactive'' computer terminals showing the reconstructions at various stages and illustrating the techniques involved. These computer displays offer a great deal of interesting information, but they are the least effective part of the exhibition. It is difficult for a visitor to try to read a computer display over someone's shoulder just as that person decides it would be fun to start switching images.

Since admission to the I.B.M. Gallery is free, it is sometimes quite crowded, and at such times a visitor may have to struggle to view the computer screens that tell the story. But the rest of the show is well worth seeing, crowds or no crowds; it brings a visitor face to face with a people who seem much closer to our own than the separation of two millenniums might imply.

The I.B.M. Gallery, at Madison Avenue and 56th Street, is open Tuesdays through Saturdays from 11 A.M. to 6 P.M. ''Rediscovering Pompeii'' will remain on view through Sept. 15. Information: 745-6100 or 745-5215.

Photos: Portrait busts are among the many artifacts in ''Rediscovering Pompeii,'' at the I.B.M. Gallery of Science and Art. (Nancy Siesel for The New York Times)